966 resultados para Marine animals


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The first concept of a new library was introduced in 2001 by a faculty member at the University of Texas Marine Science Institute. The suggestion for the construction of a new library was based on two specific reasons: existing library is located in one of the most vulnerable buildings to hurricane damage and the library has outgrown its current space. This presentation provides a general overview of the current status and changing needs of the Marine Science Library and how the idea of a new library finally became a reality

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This paper reviews the effectiveness of Gammarus scope for growth (SfG) as an indicator of water quality. In addition, the link between physiological changes and effects at higher levels of biological organisation is addressed. Exposure to a range of toxicants resulted in decreases in Gammarus SfG which were qualitatively and quantitatively correlated with subsequent reductions in growth and reproduction. Reductions in SfG were due principally to a decrease in energy intake (i.e. feeding rate) rather than an increase in energy expenditure. Gammarus pulex is an important shredder in many stream communities and stressed-induced reductions in its feeding activity were correlated with reductions in the processing of leaf litter by a semi-natural stream community. Hence, changes in the physiological energetics of Gammarus provide a general and sensitive indicator of stress which can be linked to effects at higher levels of biological organisation. Under long-term stress and hence prolonged reductions in SfG, animals may adapt by modifying their life-history strategies and producing fewer, larger offspring.

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As the atmospheric levels of CO2 rise from human activity, the carbonic acid levels of the ocean increase, causing ocean acidification. This increase in acidity breaks down the calcified bodies that many marine organisms depend upon. Upwelling regions such as Monterey Bay in California have pH levels that are not expected to reach the open ocean for a few decades. This study reviews one of the common intertidal animals of the California coast, the Owl Limpet Lottia gigantea, and its genetic variation of the plasma membrane Ca2+ ATPase (PMCA) in relation to the acidity of its environment. The PMCA protein functions in the calcification process of many organisms. Specifically in limpets, this gene functions to form its protective shell. Single-nucleotide polymorphisms (SNPs) were found among five sections of the gene to determine variation between the acidic environment population in Monterey, California and the non-acidic environment population in Santa Barbara, California. While some variation was determined, the Monterey Bay and Santa Barbara Lottia gigantea populations are not significantly distinct at the PMCA gene. Sections B, C, and D were found to be linked. Only one location in Section B was found to have an amino acid change within an exon. Section A has the strongest connection to the sampling location. Monterey individuals were seen to be more genetically recognizable, while Santa Barbara individuals showed slightly more variation. Understanding the trends of ocean acidification, upwelling region activities, and population genetics will assist in determining how the ocean environment will behave in the future.

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A biota marinha está exposta a uma elevada quantidade de substâncias tóxicas que podem causar graves problemas ao ambiente. As esponjas (Porifera) e os mexilhões (Mollusca) por serem sésseis e filtradores são utilizados como bioindicadores de poluição. A experimentação com aquários permite a realização de ensaios controlados, acompanhamento da resposta a diversos poluentes, concentrações e tempo de exposição. Os objetivos deste estudo foram: I). avaliar a imunocompetência através da expressão de proteínas do sistema imune Fator Inflamatório de Enxerto AIF -1 e pP38 por teste de ELISA (do inglês, Enzyme Linked Immuno Sorbent Assay) em esponjas expostas a poluentes, II) acompanhar a expressão das proteínas AIF-1 e pP38 nas cinco espécies de esponjas marinhas: Aplysina fulva (Pallas, 1766), Chondrilla aff. nucula Schimidt, 1862, Dysidea robusta Vilanova e Muricy 2001, Polymastia janeirensis (Boury-Esnault, 1973) e Hymeniacidon heliophila (Parker, 1910) após exposição a lipopolisacarídeo (LPS) de E. Coli III) avaliar a expressão das proteínas AIF-1 e pP38 nas espécies C. aff. nucula e P. janeirensis após exposição a dodecil sulfato de sódio (SDS) IV) avaliar a mortalidade de mexilhões quando expostos ao dispersante Triton X-100 e esgoto doméstico in natura. Os resultados indicam que as esponjas A. fulva, C. aff. nucula, D. robusta e P. janeirensis expostas a 20 μg/mL de LPS por 30 minutos, uma, três, 24 e 48 horas apresentaram aumento de expressão da proteína AIF-1 em relação ao controle, com diferentes tempos de resposta para cada espécie. A esponja H. heliophila exposta a 30 μg/mL de LPS apresentou diferença significativa na expressão de AIF-1 em relação ao controle na exposição por 30 min, uma, quatro, 24 e 48 horas. Contudo, não houve diferença significativa na expressão de outra proteína, a quinase pP38, nesses ensaios. As esponjas C. aff. nucula e P. janeirensis foram expostas a 0,25 mg/L de dodecil sulfato de sódio (SDS) por 24 e 48 horas. C. aff. nucula apresentou aumento da expressão de AIF -1 quando comparada ao controle em 24 e 48 horas, mas para P. janeirensis não houve diferença significativa. Os mexilhões Perna perna foram expostos a poluentes de duas maneiras a detergente Triton X-100 0,10 g/L por três, seis, 12 e 18 horas que induziu diferença significativa na mortalidade em seis, 12 e 18 horas em comparação com o controle e a a esgoto doméstico in natura diluído na proporção de 1:50 não houve mortalidade no tratamento ou no controle. A variação da expressão da proteína AIF-1 observada nas cinco espécies de esponjas marinhas confirma a utilização dessa proteína como eficiente biomarcador de estresse. Os mexilhões foram bons bioindicadores da poluição por detergente.

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From a special issue: A Brief History of the Charles Darwin Foundation for the Galapagos Islands 1959-1988

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The Sierra Leone River Estuary is a relatively young drowned river valley, it is shallow except for a deep channel which passes close to the Freetown shoreline. The upper reaches merge into a network of creeks and channels fringed by large areas of mangrove swamps. It is a tidal estuary of the semi-mixed type with the saline oceanic water entering it on a diurnal cycle. The climate of Sierra Leone is marked by a very distinct change between a very wet rainy season and a dry season. The tidal range of the Estuary (spring 3.03m; neap 2.28m) does not impede normal use of the harbour. The tidal variations can be felt as far as 42 miles inland along the water courses of the Sierra Leone River and its tributaries. The volume of fresh water entering the Estuary is large during the rainy season and greatly reduced during the dry season. Consequently there is a marked fall in salinity during the rainy season and higher salinities due to the marine influence prevailing during the dry season. The nature of the shores and bottom, the hydrography and chemistry of the estuarine system have been outlined in relation to the prevailing climatic conditions.

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A decade-long time series recorded in southern Monterey Bay, California demonstrates that the shallow, near-shore environment (17 m depth) is regularly inundated with pulses of cold, hypoxic and low pH water. During these episodes, oxygen can drop to biologically threatening levels, and pH levels were lower than expected. Weekly water chemistry monitoring revealed that the saturation state of aragonite (the more soluble form of calcium carbonate) was often below saturation and had a moderate positive relationship with pH, however, analytical and human error could be high. Pulses of hypoxia and low pH water with the greatest intensity arise at the onset of the spring upwelling season, and fluctuations are strongly semidurnal (tidal) and diurnal. Arrival of cold, hypoxic water on the inner shelf typically occurs 3 days after the arrival of a strong upwelling event and appears to be driven by upwelling modulated by internal tidal fluctuations. I found no relationship between the timing of low-oxygen events and the diel solar cycle nor with terrestrial nutrient input. These observations are consistent with advection of hypoxic water from the deep, offshore environment where water masses experience a general decline of temperature, oxygen and pH with depth, and inconsistent with biochemical forcing. Comparisons with concurrent temperature and oxygen time series taken ~20 km away at the head of the Monterey Canyon show similar patterns but even more intense hypoxic events due to stronger semidiurnal forcing there. Analysis of the durations of exposure to low oxygen levels establishes a framework for assessing the ecological relevance of these events. Increasing oceanic hypoxia and acidification of both surface and deep waters may increase the number, intensity, duration and spatial extent of future intrusions along the Pacific coast. Evaluation of the resiliency of nearshore ecosystems such as kelp forests, rocky reefs and sandy habitats, will require consideration of these events.

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The dinoflagellate Alexandrium minutum and the haptophyte Prymnesium parvum are well known for their toxin production and negative effects in marine coastal environments. A. minutum produces toxins which cause paralytic shellfish poisoning in humans and can affect copepods, shellfish and other marine organisms. Toxins of P. parvum are associated with massive fish mortalities resulting in negative impacts on the marine ecosystem and large economic losses in commercial aquaculture. The aim of this work is to improve our knowledge about the reliability of the use of marine invertebrate bioassays to detect microalgae toxicity, by performing: (i) a 24- to 48-h test with the brine shrimp Artemia franciscana; (ii) a 48-hour embryo-larval toxicity test with the sea urchin Paracentrotus lividus; and (iii) a 72-h test with the amphipod Corophium multisetosum. The results indicate that A. franciscana and P. lividus larvae are sensitive to the toxicity of A. minutum and P. parvum. LC50 comparison analysis between the tested organisms reveals that A. franciscana is the most sensitive organism for A. minutum. These findings suggest that the use of different organizational biological level bioassays appears to be a suitable tool for A. minutum and P. parvum toxicity assessment.

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Revisión bibliográfica de la situación actual del Deporte Escolar para tener una visión real, deportiva y educacional del mismo dentro de la disciplina del ciclismo en esas edades; proponiendo un modelo de gestión deportiva orientado a las escuelas en general y a las de ciclismo en particular del modelo educativo del Deporte.